Measurement of blood pressure, in general at a hospital and the like, plays an important role in a medical examination of the human body. Therefore, it usually is carried out at the beginning of medical examinations. Recently, blood pressure measurement using a sphygmomanometer for domestic use available in the market is popular among even healthy persons, so that a change in blood pressure is checked at any time for monitoring the condition of health.
Systolic blood pressure of a young healthy person is maintained at around 120 mmHg, and diastolic blood pressure at around 70 mmHg, and the integrity of the blood vessel wall is maintained so that the blood vessel can cope with any change of environment.
However, in case of some types of diseases and in some aged persons, the integrity of the blood vessel wall is lost and like an old rubber tube. Therefore, the blood vessel cannot tolerate an increased blood pressure caused by changes of the environment, physical condition, atmospheric temperature, strain in the body and mind or the like, and accordingly, there is a danger which can result in a rupture of the blood vessel wall.
An apparatus for measurement of blood pressure used widely at a hospital and the like today consists of a rubber bladder (called "manchette") which is wound around the upper arm and a detector for Korotkoff sounds. In the measurement using this kind of apparatus, first the brachial artery is blocked by increasing pressure of the rubber bladder with air using an air charging apparatus. Second, the air pressure in the rubber bladder is gradually lowered. Korotkoff sounds generated by intermittent jet flow of blood are monitored. The maximum (systolic) blood pressure and the minimum (diastolic) blood pressure are determined by checking the cuff pressure with the gauge indication in case of a Tycos type sphygmomanometer having an analog indication or by checking with indication sounds or indication lights and a reading of a pressure indicator in case of a sphygmomanometer having a digital indication.
In measurements using the above conventional apparatus, a region for measurement is restricted to an upper arm, and movement of the human body is also restricted. Further, the above conventional apparatus is too bulky to carry, therefore the conventional apparatus is not suitable for being carried with a healthy person for easy measurement of blood pressure at any convenient time during daily activities or on a journey.
The present invention was made considering the above mentioned problems of the conventional apparatus for blood pressure measurement.
It is an object of the present invention to provide a measuring apparatus for blood pressure which enables us to correctly search a location of an artery appropriate for measurement and to correctly measure blood pressure at the measuring point at any time. Because of a small size, it enables us to carry out easy measurement of blood pressure at any region of a human body. Frequent measurements during free activities of the body are important to prevent apoplexy.